This application claims the benefit of Korean Application No. 2001-42348, filed Jul. 13, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated hereby by reference.
1. Field of the Invention
The present invention relates to an optical disk drive, and more particularly, to an optical disk drive having a function for dynamically controlling a skew between an optical pickup and a disk recording surface.
2. Description of the Related Art
An optical disk drive is a machine that reads data from and writes data onto a disk, which is a recording medium, by emitting a laser beam onto the disk.
In FIG. 1 an optical disk drive includes a drive main body 10, a tray 40 having a surface 41 on which a disk 1 is placed and transported in or out of the main body 10, a frame 20 rotatably installed in the main body 10, and a chassis 30 supported on the frame 20. A turntable 32 on which the disk 1 transported by the tray 10 is mounted and an optical pickup 31 moved in the radial direction of the disk 1 for recording and reproducing data on the disk 1, are mounted on the chassis 30. Relay gears 13a, 13b and 13c mesh a loading motor 11 with a rack 42 disposed on the bottom of the tray 40 so that the loading motor 11 transmits power to the rack 42. A cam member 12 having a cam groove 12a is fitted into a cam protrusion 21 of the frame 20. The cam member 12 receives the power of the loading motor 11 to move the cam protrusion 21 up and down while sliding from side to side. Thus, as the cam member 12 moves from side to side, the cam protrusion 21 moves up and down along the cam groove 12a, thereby enabling the frame 20 to rotate about a rotary axis 22 supported on the main body 10.
A protrusion 12c is provided on the cam member 12 so that the protrusion 12c contacts a guide rail 43 provided on the bottom of the tray 40 to slide when the tray 40 moves in or out of the main body 10. The protrusion 12c slides along a linear portion of the guide rail 43 until the tray 40 almost goes into the main body 10 and is slightly displaced to the right of FIG. 1 at a slanting portion 43a thereof, thereby allowing a gear 12b of the cam member 12 to mesh with the relay gear 13c. Consequently, the power of the loading motor 11 used for moving the tray 40 into the main body 10 is also the power used for sliding the cam member 12.
In FIG. 1, when the disk 1 is loaded on the tray 40 and introduced into the main body 10, the cam member 12 turns to rotate the frame 20 so that the disk 1 is mounted on the turntable 32. Then, the turntable 32 rotates to enable the optical pickup 31 to reproduce information recorded onto the disk 1 or record new information onto the disk 1.
To form a focused light spot on the disk 1, light emitted from the optical pickup 31 must be incident perpendicular to a recording surface of the disk 1. If the direction of the incident light deviates from the perpendicular angle, forming a focused light spot on the disk 1 is difficult. As a result, errors may occur in recording and reproducing data. Thus, to form a focused light spot, the angle between the disk 1 and the optical pickup 31 needs to be adjusted accurately so that the light is incident perpendicular to the recording surface of the disk 1. Generally, the adjustment is called a xe2x80x9cskew adjustment.xe2x80x9d
The optical pickup 31 has a servomechanism for dynamically controlling or displacing an objective lens so that light is focused on the recording surface of the disk 1. However, if the optical pickup 31 is skewed relative to the disk 1 at an angle greater than 1xc2x0 due to process errors in the disk 1 or the surface of the turntable 32 on which the disk is to be placed, the skew between the optical pickup 31 and the disk 1 may not be completely compensated for simply by the servomechanism of the objective lens.
Accordingly, to more precisely perform recording and reproducing, an optical disk drive with a function of dynamically controlling skew between the disk 1 and the optical pickup 31 is highly desirable.
Accordingly, it is an object of the present invention to provide an optical disk drive having an automatic skew adjustment function.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing an optical disk drive including, a main body, a tray, driven by a loading motor, and transporting a disk in or out of the main body, and a base chassis on which an optical pickup emitting a beam onto a recording surface of the disk is mounted. The optical disk drive also includes a rotary chassis, installed to rotate with respect to the base chassis and having a turntable on which the disk is to be placed, and a skew adjustment mechanism controlling skew between the disk placed on the turntable and the optical pickup mounted on the base chassis by rotating the rotary chassis.
The screw adjustment mechanism includes a cam member, driven by the power of the loading motor and having a predetermined cam groove, and a cam protrusion formed at a free end of the rotary chassis to fit into the cam groove. When the cam member is driven by the loading motor, the cam protrusion slides along the cam groove, thereby raising the free end of the rotary chassis.